无法使用对象键引用Javascript中的方法

Question

I have a set of methods for validating input stored in a variable val such that I can call them like val.email or val["email"] . I'm trying to create a general function that will take an object and apply the validation function to each value based on the keys. My attempt is as follows:

const validateInput = data => {
  let errors = {};
  const keys = Object.keys(data);
  keys.map(key => {
    const error = val[key](data[key]);
    errors = { ...errors, ...error };
  });
  return errors;
};

I get this error:

TypeError: val[key] is not a function

However, the following executes successfully:

const validateInput = data => {
  let errors = {};
  const test = "firstName";
  const errors = {...errors, ...val[test](data[test])};
  return errors;
};

When I log keys I get an array of strings and when I log typeof key I also get string, so I don't understand why it will not work within the map function.

Thanks in advance.

Answer 1

Thanks to Jonas above I was able to figure it out. I'm comparing two fields (password and password2) inside of one function. The following code works:

const validateInput = data => {
  let errors = {};
  const keys = Object.keys(val);
  keys.map(key => {
    let error;
    if (data.hasOwnProperty(key)) {
      switch (key) {
        case "password":
          error = val[key](data[key], data[`${key}2`]);
          break;
        default:
          error = val[key](data[key]);
          break;
      }
      errors = { ...errors, ...error };
    }
  });
  return { errors, isValid: isEmpty(errors) };
};